Isosceles Triangle

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Isosceles Triangle

by dumb.doofus » Sun May 24, 2009 8:45 pm
In isosceles triangle ABC, what is the
value of ∠C?
(1)The measure of ∠B is 47°
(2)The measure of ∠A is 96°
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Re: Isosceles Triangle

by shah395 » Sun May 24, 2009 9:00 pm
[quote="dumb.doofus"]In isosceles triangle ABC, what is the
value of ∠C?
(1)The measure of ∠B is 47°
(2)The measure of ∠A is 96°[/quote]


A B C D E

Question Type: Value

Given: - You know it is an isoceles triangle...
- Two angles have to be equal..
- A + B+ C = 180

To Find: Value of angle C

Statement 1 -
Angle B is 47 degrees...
A+B+C = 180
A+C= 133
STOP !! Lot of possibilities

Cross out choice A & D

Statement II
Angle A is 96 degree..
Think about it... since two angles have to be equal... Angle B or Angle C cannot be 96 degrees.. (the total can not be more than 180)
so angle B and C are equal ... or... (180 - 96)/2 = 84/2 = 42 degrees
Angle C is 42 degrees

Cross out choice C & E

[b][u]IMO - Answer should be B[/u][/b]

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by dumb.doofus » Sun May 24, 2009 9:05 pm
Cool.. :-) you got it right..
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Re: Isosceles Triangle

by dmateer25 » Sun May 24, 2009 9:18 pm
dumb.doofus wrote:In isosceles triangle ABC, what is the
value of ∠C?
(1)The measure of ∠B is 47°
(2)The measure of ∠A is 96°
These statements seem to contradict each other since statement 2 tells us that B and C = 42.

Is there a typo in statement 1? I believe it should read (1)The measure of ∠B is 42°